public class Singelton03 {

    private static Singelton03 singelton;

    private Singelton03() {
    }

    public static Singelton03 getInstance() {
        if (singelton == null) {
            singelton = new Singelton03();
        }
        return singelton;
    }

    public static void main(String[] args) {
        Singelton03 singelton1 = Singelton03.getInstance();
        Singelton03 singelton2 = Singelton03.getInstance();
        System.out.println(singelton1 == singelton2);
    }
}
